SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '23013f585b8ff0a649c625a97a71912f041beb1337bcdb2e1ee7888b88199a51' 
  AND token = 'r8C6WearNuVMnaU5klzdzjF5mUy4uCYk4ONTpDKDiWE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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