SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a7bf5a0aeff4ba113fe799a6e8f0989c334098d6fe5c0d510386cd1bc2fbd0bb' 
  AND token = 'X3UdWnUKSk6zCkOEfSxKSIQcvglU5KTYrB5CTSItPRw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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