SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6c8c4d3e13eef7b51c0fadbbb0c068385379dd5b9425a405242d05b83f8ee467' 
  AND token = 'qlyrvZmshbFSKaQXHZ1GwFQUZYY7bNpGu/BiQaXfpG8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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