SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '679f8ba31b47d4f3e0bf2b141d5600fc7573477a9c91886da91c5a70844c7f24' 
  AND token = 'LSBZSIcmYFSF8s7lmpCWKz79CnRGnLQE1lg/API8tV0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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