SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f38d1550f9ebe1d2818866a62edfff81106e4b69d030f06737cae7dbc16b4b24' 
  AND token = '9iSzRXpILIDtTsfdlxSSn2W0k/iolABbysUSb1hLy28=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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