SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4b35282a526ac1608ea07ea9a6219635bc8b8995aa0ad239b440078d09bfa1bb' 
  AND token = '5uFD9+iSqYr8IrK3xip6/jCMmd2Fusy8JXvaAhDBlXo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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