SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fcaf9c9e8148a7719b40e47eb541bf53a80495cdf75b49a9096879ca5d8231f8' 
  AND token = '+aGk0M3dKNmTiVDOT/fpyjLty5DgwypAW0l8bLv9TnU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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