SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '49c2dbd682051342f08e10d6b100b9ee04bcc8bd441ce5bd82a048be918bcc7c' 
  AND token = 'gsRY0gSAirxc6qxLGsfb4Y/Ekfwdwc/KR2CTQIYgBn0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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