SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9ebcf5380ba281c5360907a20761b91b86a2b07edf1c50244e05bbacff319025' 
  AND token = 'j1AZfRQl0I9JAY6bJRXs5PNOnlaU+/rtztgAqL+9zmo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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