SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '248ea2578172e558611fd63a00d32445b4f09c855e6f0747914000e25dcbb903' 
  AND token = 'AzSySBg3HpnmadqE2krzibn8qaB3upEgphdk0QVjrAQ=' 
  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"
    }
  }
}