SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e3ca1bce19937aa7453cbc284788eb9041c2ab5fa64a5c810ffbc9db3689e7c4' 
  AND token = 'CF2Gvlh30JcnQ8qvnq8BOztZYdnizbFyoB2pO+vLM2w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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