SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b2852d1c0be464c3584118d4b89e10939c1eb95c7a6f6a0ab56041670d1b3107' 
  AND token = '75V2V2nwrfOcfrvXBnbXEMBYAURaF5o5M57xLbh+veQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}