SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9a0ff285bb2330c629a1ca023e7f5b60a788f58a836bd974515a94532cb0edc2' 
  AND token = 'vxN3tYSwjHjsHqO4vjKGK7PJ1tR4W1RMj+BVoKynIi8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00054

JSON explain

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