SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd23a565ecfc38da7efb263472ee9131d275a4aa15d4ad63308ecd1a2cdc6bbfa' 
  AND token = '7rN32/ZgvH0aHhEMXuzWbHMgES3f8QwLu1SWzUgUwSA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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