SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c1c65b971ada1ba1764d9131b56c525a3e024295865248dac1bb213c92e8fb68' 
  AND token = 'XsTzwr58cT6CgnN6r+IF9WGsdAi30+ZO6OSp8V/mEUQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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