SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd68e298a790dcd68d2488f31b2542d8ee8259931cb80c062d8ac166eacde4191' 
  AND token = 'hDwjGU2lm+1JqFtpwneijpaJBYypk36XHeE9ylAlOmI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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