SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9954903a02fda01d6fb987e193fd3d87e0e2b038b73dedf688403700a6de62f3' 
  AND token = 'bbLLBmEIS1ShwGrQufEqGdqYpqRZ8w3uWHSgnMOvckc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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