SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2d2ba733654299532a684472481e0376f8eff6b311b0230fd73fddb753ebf1b7' 
  AND token = 'mVOf7PgIGJNl4BAV3fjUqVVHL56nl0xFBgCXtMLlIbU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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