SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '46a6b5a0872cb0e00ca2ea328f0b6c13146b4082b382efef4567bb192df51793' 
  AND token = 'D5cS6nX9BzgRBZaGMAsbgpvVzP9tiO6ffUYmmoL4qBU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}