SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4686091c727fbfae5b3dbc9d2f885a507146b80ed1a4f696841a7cfd5ffd1e60' 
  AND token = 'UVOPsaZ7RhVdjPjv8tOAN/qJ2LTtZGxGsuElBLzz5mk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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