SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '67b8c3821f25d15b1315bb6e0ede0eba56dbe6d41caeecbf7fd180cbba396efa' 
  AND token = '8WQPG6omFGnhx0mhikAhii6JSZCKqMStAiDaSTLoy/E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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