SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '12d9d390e421dacac59ac3b83477fed439f367635c71c5ccd61e951756491c11' 
  AND token = 'zxEKUnu06PcUVaaecd6xLzWhdWxIsc7cF2WsiGua9p8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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