SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '40ddae1599959239dbd423ba8bb643839bc0d8087a818172aa6fba741b0fd1cb' 
  AND token = 'vABog7IIVU+135OfB6+MDaiHIFue11m8Isa5JpeJCds=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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