SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b192a37cffc6dce2a131e5333942749bfb4717a04aa983046a86783dc32c6cd8' 
  AND token = 'uIVUz8I33b1HA7XnLeEL6cQ9djAImZKP3dTGdETJNWE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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