SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1166f3de4ee9826c5fcf424216c92bec7bfb968f4eec389cc64d22d0617eb8f9' 
  AND token = 'UNLgqQRSjqAzAhdPI9zn4lV85S/cwGhBz5dmZlCqSo8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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