SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '87adb5446b1f0baf75ab6ef0addaf4e1873eb20a2d20244df55769b197050edf' 
  AND token = 'gFjt0H3K3H9NEuGibyTRprQNUY0l5Iep8kgXapMGUYs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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