SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '502dc3930aeff7b4803ec300b9bd1feb117e21976b1763d0474232ff8885d7bc' 
  AND token = 'hwrNeFNjK1a/6EuNBMvmHcLlOBBMuX5/4VNygToBGOI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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