SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6f31865a51382fb59d77e6a19806b94c8bb69d1989cf5e3c9ee212fa008cbe4b' 
  AND token = '/aH8hDHkVNMjZjcM/uOOLETzt/l6Zgw8T5QvIiG+eko=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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