SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '437f82336753a3507b9cba6853c2cd8b18997aab8857adf87ee7abe452bb13cd' 
  AND token = 'NURPyJ5sd5SVz2nawAFmI61eqWrGdtSPrRnbnXBXuXs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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