SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '17270ecd4af96ffb2a2bf77a29edf2641142795d077c4cbc7f07b1858cdc5be8' 
  AND token = 'CSkLC5Sj3pXmGQeKt70sDEr89vdGLJCLFSx4MjeVQak=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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