SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9a3520304e69cf638e2504714cf0e9afe51363c7614bf2fe0660ae8218d126ed' 
  AND token = 'ZG0YzmPODWt0+MbIR7Td25oj/lR34LnpDZoiGDISMqw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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