SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fc3eb0eba7e42a754136835f703405fd66236ab5cbffd4a96afd0736b57ab116' 
  AND token = 'WfYSScJFIdbWbrmI/AHVFFTxSEK63ljiDCmxmVr6Rrw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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