SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b8e5fd4107e6ef45be748387664d1ace492236822a298f80e690b44176102395' 
  AND token = 'Y+FiANwjQqsXa73uIvqrMK2n13dhlgJV6jp+x+t8HKI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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