SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '79ccc094fa145075727225171f553a7c8c6883217987ea214214b95f3cf7c5a7' 
  AND token = 'EKKBeKPCDgMv87VGCaCTOzV5SToglxlsMm7CYAryWGA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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