SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0ffea74cfc980ebf4e80269550b137bc7d97c0d60edc77284c45316daae29778' 
  AND token = 'Wl4Q5t7v8C8iqokrH+xfepm2JKdgFElTSm/6MAROcLA=' 
  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"
    }
  }
}