SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3d2309749a6addeb7677c45377df4317c51d0594cca64a40efb9dab3e731c725' 
  AND token = 'S/bf3UqaORNW5fCURLAl8W0Rx9wn//rdXuFGsZzI7gc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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