SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '350dcd42baf3d47999caf299bb086c11395cf79a66745a1d18ff6ea76247eb97' 
  AND token = 'HMZQu8U7VFbLAc87bwok/UYFqMOcdjEJ8196WiXnFBE=' 
  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"
    }
  }
}