SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7c4f19d38ee967b9398ca7d8267e4e8a23ade36ff11bd2f3c32bca8f28a01055' 
  AND token = 'GqXriJXBkCE7gNFmuKWKhA0fFSjO1kQokYeXng7hIWw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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