SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b8e787a93992b5bc2cb4077ef248f7cceea89523c9ea548734b379c9eb9571d9' 
  AND token = 'PKxTtrkoQIF3QqLCBP56gDwdsFaGK5YOawfrSm+CVeE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00061

JSON explain

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