SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '140b57674deed46c018aa681fe66077387040ce9958f729933a6414c791c2aeb' 
  AND token = 'fPLcwInbuWzhL/2QfcJkhEH/EiODCw/gTkzhkBoohqE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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