SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f6034644753ed2c1470816de75b0f85e71f9fad6b84bbe2cbd33c787b017bfdd' 
  AND token = 'ZG9jgvdCNVxvSdwSXNaS93eNhQuWJfkqc4ZCxvX2opM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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