SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2b4ac678332d6a1666dcfbdfb85776792ed71b3b6a62d8a676e18259e582cefd' 
  AND token = 'Kbx03tWoKmsqRO0J84XFtXHGVsdMGdSg3lvjhfiGpZ0=' 
  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"
    }
  }
}