SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '96516f30e5298f3f58e1ffb67026a78c291dfdda198ad6292919864142c88d21' 
  AND token = '2iBuPNpMpQwH+TjPeCoDKaYIthr7/vuJjqFw4qqvMfw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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