SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '42a8cbc781b3ff9dadfb07726c74a564b3bbebe6706a0cdb22ac11feedba7446' 
  AND token = 'Bqm0GF/9FdKs55TIktbIHvtJxrjJXXZvqxwVOcRFhwg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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