SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bb1668d84698b4b2ffc405b234f89f4216d82d601598346d988f33bc22fd33e9' 
  AND token = 'nU9QhdWM9vJYr7HDGr+bb5NXKIhMwG67L+81HFqYKuI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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