SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd14b5b62569b7142668e6f12fcc08a7d714a7d26b68891438a329155e76d1cfd' 
  AND token = '3G7usWvyhnG0UTQGzn9eFqJ9MzbLSHJmEO2QUP79xJY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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