SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bf23d20167d588e3948df208dca86adbff4df5635244244266853a54df6ec7ec' 
  AND token = '/KKpd3ZbI7zoBQHegQWzxCY9Qak/xwnDHJ9sw6Rt9CY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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