SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8ece3807c847f7ca525efe86754a6c2cbcfbc59727a4b59648a78d38c09be1ca' 
  AND token = 'skVk+cJAwLPqEn41jzbqxyHy2U0PXrdWAtgaS6rEqt8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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