SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0f921f6d6f4ab060b55016350b258c670aa2beff7039528ee100c45301632c85' 
  AND token = 'qpIoEXuI2VYsebWsHWOgfZW4ruvmqEPmGiNm1e8qL0E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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