SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fc5583e70b1eee8049ac058ab50f5dc3873c5b98b59896c129842b1251241876' 
  AND token = 'fTkzuSdLQyU7mKb2wz65vZXj/PhipWgCwsV/tqrBYNE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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