SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bcb4cb8badf07965174b0f352cfff30ffedbddf66928f267fa1caeedf5365886' 
  AND token = 'GWjB9Vh1ThXWPKWl9lyv+iueNEJncoNKGOFgQHZj86E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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