SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '00876ac2ca1c8ca428bcec19e0e876fb422352431d54b0966bad5d154631b180' 
  AND token = 'W3yHF4cgoMsKxTJgWX5/hbR0P3EBjTsfShJBUk+JYQw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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