SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '804801f8fe408ff9af30c39c45c4cc6322285cab79368ff7f76f9ce79d23e799' 
  AND token = '+oGYgVboBjjn8v10rMQMzUNqbCultloFJ1PR5njR2Iw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00066

JSON explain

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