SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7293e043337e5bfd91894dca6ac386df38d3e9a90c5fde12a51af5cdeb55597f' 
  AND token = 'YYQpQL2laBEGKN7+U0c1AwEQeGNmXVlO10GcfBfmnr8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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