SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '40d2680f1bb7c57f23a8bfcc3d2a239716481256f1b32b4f57d86e0ec8a4bcaf' 
  AND token = 'cRBJCnxL/GkumtpIqBY7ZF/bhxj0g7yKXa6w69QtoO8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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