SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd0c288560c60ea757d734eb5ba58ca93c9e1f2bc8697549b20120481fdca8af6' 
  AND token = 'phOxXXtAODhDpB+8NRkkqooliquoDiRA0o+D5f6nMTM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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