SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6de76d9d3383f80ca5f84beb15c481db9975a5e1e69d1dd684dfa6e634bd1296' 
  AND token = 'iyHhqH79K+KgMa1n15GsxVSebtvOsZ/zyxSGTxNjzdw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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