SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '00c319ef4856dedb2552a9d32a875ae50138b37cb4c441f7f82232417e4bb1d5' 
  AND token = 'K0ljr3GEVB/ZThBb6iTkPtqRENQR1SWf2VLGHxoV5jI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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