SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '127ce26957ead8f751aed9a71b68919a0627047da4674ae1f873b28ecb004fdd' 
  AND token = 'zaSqyG2lKxPQKmvxCXMOWMvZEy9JQ35hZhmKbQipXmk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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