SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a0ee05af41481f3c0bafe11ec3e7d0af994006055c2b8f8dda269a166ecdb6c1' 
  AND token = 'B+H+TZSy1hqRkuSgLE8MULTDQkEHjm7onBz2ZjJ98Pc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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