SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5fee97fdcfd58cc511adb641aa4e053d34927139f7806393fca9f5aef289f3d3' 
  AND token = 'jniZ8e9xaovlRsJNorC8azL3qgMdgjC8ihOvInhea8c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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