SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6ab79599a90c1ca01a394f9def3df42175b36dca20e1e3423b4db91898d7c8f6' 
  AND token = 'W8Odt+D+dEJ+n42JUovTJWRsE8F9DFSdUuqQTuUDWqE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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