SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2141170f4b70cba9348ac5d964514f7ed6dbab5d854388e93b2659b26ddc9214' 
  AND token = 'wqT3pNJWT9Q0sDHyFoj4zEeR4ZWhv/bBzMPgyGlGSYA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}