SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd3745638bfdad30213fcc3367b371100f9e37bd2bdbcdc83f138a7a9b3fa445c' 
  AND token = 'KLElVo/drcQ2Okv6g+OiwrXejMsXB//BKqw/czqcGH4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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