SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7ffde9ff889c5cb5a153e8f2940ca4d2827f0eac2b4f6ea237d79b9a27a3ad31' 
  AND token = 'sqxhk/F2Ztq62JJLly+Cm3J9b1qOkKaoRjhzVp90pvs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}