SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eb39af9336ce05ecc7b3c749c69d2a60f19933512434a32838a80d8428684111' 
  AND token = 'MMkye724g29TuXoJJYMpRoWf+FsPomabKvSP+ZIByY4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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