SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f390ac881a2c9ef7d2e0d79d03170ae7613b6e553d94bccc366ad684a52a59a6' 
  AND token = 'jy99C54SQASyHVlBuHxwWdAlZTG0voQ0Ze9OgojagJ8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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