SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '475a78d6c4e92663f1dfe575cadb6fee39cc6c1d9c089781cc7763aef477e10d' 
  AND token = 'gPPVR5IUMPekUwPZ0tEGzBasXw+UOPP0ZtfLNEPPVgY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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