SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '44b0f80583c1224d1d9688247ead3103cca346278d194c8b8dd775e5daae47e5' 
  AND token = 'gK6y1Pr/zaW3adR8+BdmEWO13XQoGWOtjrd/EJsZJpI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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